At one time a metronome was regularly to be found on top of the upright piano in the family home parlour, together with the obligatory piles of sheet music whether of Chopin Etudes, Beethoven sonatas or songs from Rodgers and Hammerstein's Oklahoma. It is instantly recognisable as a pyramid-shaped wooden box of the order of 8-12 inches (20-30cm) in height.

Swing and Beat

The metronome is an application of the principle of the pendulum, in this instance a double-weighted – a single rod or bar, with one weight above and one below the bar's pivot point. At rest the pendulum is vertical, but when set in motion it swings alternately to the left and right. The weight on the upper arm of the pendulum is mounted on a movable slide, its position being used to set the period of oscillation. A scale marked on the rod indicates the number of beats per minute (bpm) that the metronome is required to 'display'; the higher up the rod the weight is moved, the slower the pendulum will oscillate. A heavier weight mounted at a fixed position on the lower arm of the pendulum counterbalances the upper arm, and is usually hidden within the box that is used to house it. A spring-driven mechanism – an escapement – imparts pulses to the pendulum, sustaining its motion without otherwise affecting it. An audible sound – usually a click – is generated when the pendulum swing reaches its furthest point to the left or right. These clicks are the beats per minute that are set by moving the sliding weight up and down the upper arm of the pendulum. A small clip or catch is used to hold the pendulum at rest when the metronome is not in use.

Why and How is it Used?

The metronome can be used for anything that requires an audible signal at intervals of between about 40 and 200 beats per minute, but its commonest use is as an indicator of the 'correct' speed to help people who are practising musical instruments to play them in time.

Western music notation uses symbols written on one or more staves. These symbols include notes – minims, crochets, quavers etc – and their equivalent rests, as well as time and key signatures. It is a proportional system, that is to say how long each type of note or rest lasts relative to the other types is well-defined¹, but their absolute time duration is completely undefined. To this standard notation it is necessary to add further indications, such as tempo markings (usually Italian terms) like adagio (slowly), andante (at walking pace), allegro (quick, lively) or presto (quickly), if the performer is to reproduce what the composer has in mind for his work. However these terms are quite broad in scope: an adagio is typically taken at 60 to 70 bpm, an andante at 80-100, an allegro at 120-160 and presto at around 180 bpm. These figures are a matter of common practice in interpretation rather than measurable parameters, and have varied considerable with time: an adagio marking on a 19th-Century metronome suggests 60 bpm, a 1950s version 54 bpm and a modern electronic one 70 bpm.

Looking at a sheet of music you may see at the top, just above the first stave, something like crochet (quarter-note) = 120. If the time signature is given as ²₄ it means that there are two beats to the bar (measure), each beat being a crochet (quarter-note) in duration. When played at the 'correct' speed, a metronome set to 120 bpm should beat twice in each bar. Be aware however that the music may not be notated in crochets; each beat might comprise four semiquavers (sixteenth-notes).

Twice in this section we have used the expression 'correct' speed and this is where a problem may arise. Metronome markings when they appear on a musical score enable a definite speed to be specified. However, composition is one thing, interpretation is another. It has been said that composers are often not the best interpreters of their own music, even if they do possess the technical skills to execute what they have written. For this reason, teachers sometimes tell their pupils that metronome markings are there for guidance and need not be observed too strictly. More important is what the performer 'feels' is right. Skilled interpreters may be better able to realise what the composer's true intentions are than is the composer himself.

Origins

The mathematics of simple and compound pendulums had been described by Galileo Galilei in the early 17th Century and a method of using a pendulum in conjunction with a spring-balance and an escapement mechanism to regulate mechanical clocks was in use by the 1680s.

A device for musical timekeeping based on the principle of a simple pendulum was first made in 1696 by Étienne Loulié (1654-1702), a French musician and music theorist, but it lacked any audible signalling; the user had to judge by eye when the pendulum was in the centre position. It also lacked any clockwork mechanism to sustain the motion of the pendulum, so the device soon stopped. Other inventors such as Joseph Sauveur² (1711), Enbrayg (1732) and Gabory (1771) are also known to have made attempts at such devices. The renowned English clockmaker John Harrison described one in 1775. Their attempts were largely unsuccessful, mainly due to the long length of a simple pendulum required to have a frequency of oscillation down as low as 40 beats per minute.

Intellectual Property Theft

The mechanical metronome with which we are familiar today was patented by, but wrongly attributed to, a German showman and maker of automata³, Johann Nepomuk Maelzel (or Mälzel). Recognition as the true inventor should have gone to another German – Dietrich Nikolaus Winkel – who produced in Amsterdam in 1812 what he described as a musical chronometer. Winkel realised that by using a double-weighted pendulum, he could reduce its length to a practical size, but sadly he failed to take out any patent for his invention. Maelzel saw Winkel's chronometer in Amsterdam – he may even have worked with him on it – and attempted to pass it off as his own. In truth all Maelzel added to Winkler's invention was a calibrated scale and the name Metronome. He applied for and was granted patents in England and in Europe in his own name, and began manufacturing and promoting the 'new' instrument. In the English patent granted in London in December 1815 for his Instrument or Instruments, Machine or Machines, for the Improvement of all Musical Performance, which he denominates a Metronome or Musical Time-keeper, Maelzel said the device:

... is for the purpose of counting or beating the time for music, or in other words for dividing, indicating, or marking equal portions or intervals of time, whereby to regulate and determine the degree of quickness or slowness, with which any piece of music shall be performed. These equal intervals of time are measured by the vibrations of a particular kind of pendulum, whereof each vibration is indicated in an audible manner to the performer, by the tick or drop of an escapement, similar to that used in a certain description of clocks; and the said escapement, by transmitting the action of the maintaining power of a weight or spring to the pendulum, keeps it in continual oscillation, as long as the weight or spring continues wound up. The construction of the pendulum which I employ in my machine is such as to admit of readily adjusting the period of its vibrations, that any necessary number shall be performed in a minute of time, thereby to adapt it to beat or keep the time for the performance of all the different kinds of music, whether the movement of the same be quick or slow.

Maelzel and Beethoven

Beethoven was an early enthusiast for the metronome, diligently marking his scores with metronome markings in an attempt to ensure that other people played his music at the speed at which he intended it to be played. In 1817 he declared in a letter to Hofrath von Mosel:

... I have long purposed giving up those inconsistent terms allegro, andante, adagio, and presto; and Maelzel's metronome furnishes us with the best opportunity of doing so. I here pledge myself no longer to make use of them in any of my new compositions.

In the same letter he went on to suggest a marketing plan for the new device:

In our country, where music has become a national requirement, and where the use of the metronome must be enjoined on every village schoolmaster, the best plan would be for Maelzel to endeavour to sell a certain number of metronomes by subscription, at the present higher prices, and as soon as the number covers his expenses, he can sell the metronomes demanded by the national requirements at so cheap a rate, that we may certainly anticipate their universal use and circulation. Of course some persons must take the lead in giving an impetus to the undertaking. You may safely rely on my doing what is in my power, and I shall be glad to hear what post you mean to assign to me in the affair.

Maelzel had already provided Beethoven with various devices, including the ear trumpets that the composer used more and more as his deafness increased.

One of Maelzel's automata was called The Panharmonicon, a huge bellows-driven device with pipes and percussion instruments – the music being encoded on revolving pinned wooden barrels, like oversized versions of those used in musical boxes – that emulated a military wind band including, at least: piccolo, four flutes, five oboes, five clarinets, two bassoons, contrabassoon, two horns, four trumpets, four trombones, timpani, triangle, cymbals, small and large drums, and an organ bass. According to the celebrated composer and pianist Ignaz Moscheles, it was Maelzel who suggested to Beethoven that he should write the original version⁴ of Wellington's Siege or The Battle of Vittoria in 1813, a work commemorating the defeat of the French by the Duke of Wellington.

Beethoven and Maelzel fell out over this musical work. With behaviour very reminiscent of that towards Dietrich Winkel, Maelzel portrayed himself as its rightful owner, and tried to capitalise on it, claiming that Beethoven had gifted the work to him.

A Coda of Injustice

Despite his protestations, the support of various scientists and learned music journals, Winkel's claim to be the inventor of the metronome was ignored and he died penniless in 1826. Maelzel on the other hand became very rich and lived until 1838, when the boat on which he and one of his Panharmonicons (there were several) were travelling, from Havana, Cuba to Philadelphia, USA, sank and he drowned.

Modern Metronomes

Although there is still a demand for the traditional mechanical wind-up metronome, today electronic versions abound, some combining the functions of metronome and tuning-fork in one simple device. There are even metronome apps available for modern smartphones.

Trivia

Surprisingly, the metronome is not well represented in the canon of music compositions, but in 1962 Hungarian composer György Ligeti 'composed' a piece entitled Poème symphonique for 100 metronomes. It requires 10 'performers' each with 10 fully-wound metronomes. They are pre-set for different numbers of beats per minute, then started simultaneously. Slowly their clockwork mechanisms run down and one by one they stop. When the last metronome stops, the 'performance' ends. It is rarely performed!⁵